It is necessary to supply lubricating oil to gears and friction engagement elements (speed change clutch) and the like which configure the transmission of the vehicle to perform reduction of mechanical friction, cooling, corrosion prevention and the like.
Patent literature 1 described later discloses an invention that supplies a lubricating oil amount, which is required in accordance with an operating state of a planetary gear transmission, to the transmission.
Specifically, the patent literature 1 has achieved its object by the following means.
a) A speed change stage, a throttle opening and the like are detected by individual sensors, the detection signals by the individual sensors are input to an electronic control device (controller), the lubricating oil amount required for the transmission is calculated by the controller, and an electric signal indicating the required lubricating oil amount is output.
b) A first regulator adjusts the pressure of the pressure oil, which is discharged from the hydraulic pump, to a line pressure and outputs to a line pressure oil passage.
c) An electric signal corresponding to the required lubricating oil amount output from the controller is input to a solenoid valve, and a lubrication signal pressure is output from the solenoid valve to a lubrication signal pressure oil passage.
d) A second control valve is connected to the line pressure oil passage and the lubrication signal pressure oil passage, and the second control valve operates a spool in accordance with the lubrication signal pressure which is supplied from the lubrication signal pressure oil passage, with the line pressure, which is supplied from the line pressure oil passage, determined as a base pressure, and outputs a lubrication pressure to the upstream side of an orifice.
e) The required lubricating oil amount corresponding to the lubrication pressure is supplied to the transmission via the orifice. The pressure on the upstream side of the orifice is input as a feedback pressure to the second control valve.
Patent Literature 1: Japanese Patent Application Laid-Open No. 10-141480